1. Field of the Invention
The present invention relates to a washing machine, and particularly, to a dehydration controlling apparatus for a washing machine and a method thereof capable of more evenly distributing clothes within the wash tub of the washing machine to prevent noise, vibration and excess energy consumption.
2. Discussion of the Related Art
In general, a washing machine performs a function for washing laundry (i.e., removing contaminants or pollutants such as dirt, oil, stains, or the like from the laundry) by mechanically applying a suitable friction or vibration to the laundry in a laundry detergent.
For this purpose, the washing machine performs a washing stage for applying a mechanical force to the laundry in water mixed with the detergent, rinsing stage for rinsing the detergent containing the contaminant out of the laundry, and a dehydrating stage for removing the rinsed water from the laundry (i.e., dehydrating the laundry).
During the dehydrating stage, the wash tub may become unbalanced if the laundry becomes unevenly-distributed within the wash tub, causing severe vibration and noise within the washing machine.
Accordingly, a function to evenly-distribute the laundry is required for the washing machine. In the related art, this is accomplished by detecting an UnBalance (UB) amount and then evenly distributing the laundry according to the detected UB amount.
FIG. 1 is a flowchart illustrating operations related to an UB amount detecting and dehydrating method of a washing machine according to the related art.
As illustrated in FIG. 1, an UB amount detecting and dehydrating method of a washing machine includes driving the motor of a washing machine at a low speed (S11), sensing a changed amount of a motor speed (i.e., Rotation Per Minute: RPM) of the washing machine according to changes in time to thereby detect an UB amount (S12), comparing the detected UB amount to a preset reference UB amount (S13), and performing a function to evenly-distribute the laundry when the detected UB amount is greater than the reference UB amount (S14A), and dehydrating the laundry by increasing the RPM of the washing machine when the detected UB amount is less than the reference UB amount (S14B).
The detection of the UB amount (S12) will now be explained in detail.
First, a speed detecting unit mounted in the motor of the washing machine is used to measure the RPMs of the motor for a predetermined period of time and changes in the RPMs of the motor are determined.
The maximum changed amount and a minimum changed amount are used to determine the UB amount and the size of the laundry load.
The UB amount determined by employing the method is compared to a reference UB amount corresponding to a preset load amount. Based upon the comparison, when the determined UB amount is greater than the reference UB amount, the motor of the washing machine is stopped to change a spinning direction of the motor. The laundry evenly-distributing function is performed accordingly.
If the determined UB amount is less than the reference UB amount according to the comparison, the RPM of the motor of the washing machine is increased to perform a dehydrating operation in order to remove water contained in the laundry. Thereafter, the RPM is decreased thus to determine the UB amount.
When the UB amount determined is less than the reference UB amount, the dehydration is performed by a faster speed. Then, within a certain time after the RPM of the washing machine reaches a preset dehydrating speed, the RPM of the washing machine is decreased again to re-determined the UB amount. When the UB amount re-determined is greater than the reference UB amount, the motor of the washing machine is stopped to change the rotational direction of the motor, thereby re-performing the laundry evenly-distributing function.
When the UB amount re-determined is less than the reference UB amount, the current RPM of the washing machine is increased to reach a preset dehydrating speed. The dehydration is then performed for a preset time by the preset dehydrating speed to thereafter terminate the dehydration.
When the UB amount determined is less than the reference UB amount a predetermined number of times, the laundry load is considered to be a small load, and accordingly a separate dehydrating algorithm is implemented.
A method for determining a small load may be implemented by comparing the UB amount determined by repeatedly performing the operation of increasing and decreasing the RPM of the motor in a washing machine containing a small amount of laundry to reach the dehydrating speed.
Accordingly, the determination of the small load takes a long time in the related art, and the RPM of the washing machine motor is increased to a relatively high speed, which causes noise and vibration and unnecessary energy consumption.